11SF restoration: racing engine after sitting a couple months

[mixelpix]

Hello,

I am restoring a 1979 SF 1100. It's been sitting a while and I thought it might be time to run some gas through it and turn over the motor, splash some oil around the crank... She was in a front end collision earlier this year and I am slowly getting her back on the road.

I had to squirt a little starting fluid into the carbs to get her to turn over, but the battery is holding charge - which is an extra good sign as there are some mysterious electrical wirings and there were a lot of loose ends after removing the fairing - and the starter/ignition seem to work fine.

With the choke and throttle closed, however, the engine races like it is in full advance WOT. I didn't notice it at the time, but two of the boots between the airbox and the carbs (the outer ones) have slipped off and are otherwise not sealing the inlet side of the carb. Maybe this is causing a lean mixture? I'm gonna truss them up and we'll see what happens...

Anyone ever have an engine race out of control after storing for a while? Should I dissasemble the vacuum advance to make sure the timing linkage isn't stuck? Seems unlikely... I've gone over the contact breakers in the older, smaller XS bikes a bunch, but haven't ever tackled the XS11's. Before I start tinkering away (don't worry, I have a gorgeous LG I can still ride just wondering if I am looking in the right direction?

Thanks!

-pdk

[Parr8hed]

Start by checking the obvious things such as the throttle cable at the hand grip, and at the carbs. make sure that it is seated properly at both ends. also make sure that it is ajusted right at the hand grip and lubed properly. also check for air leaks at the manifolds as described in the tech section. may also need to clean the carbs well.

[mixelpix]

Thanks

A little back story:

Last November I bought a one way ticket to Redmon, OR, bought the bike and then rode it some 1000 miles down the coast. Purred like a champ the whole way. I'm not sure when the airbox to carb inlet rubbers came off. that was kinda random. The PO and I went over the bike pretty thoroughly as I wasn't about to part with the $$ before I was confident she could make it. I did a compression test, 145psi even across all 4 carbs., inspected the brakes, hoses, tires, pressure was consistent in the first week of owning her. He had put fresh fluids in and they looked clean when I checked with a fresh clean dip stick. I changed them again after getting home. There is some mystery wiring, a weird onswitch under the fuse box, a few extra lights but otherwise the charging and ignition systems seemed to function just fine. The transmission slipped into a false neutral once or twice and I'm sure has seen better days, but was otherwise responsive and solid for less than crazy riding. I caught a few straightaways around 115... What can I say, the speedo goes up si high!!!

Ahem. I was - oh duh, now I know when the carb boots popped off - letting her sleep over the winter and was otherwise just doing some superficial clean up and basic fluids/filters kinda stuff.

January 20th I fired her up and took her into town to put some fresh gas in her. Slam, front end-o. That must've been when the boots popped off...

So, I rode her home, took the necessary photos, kept the broken fairing, the windshield I flew through, the other dudes side view mirror, etc... The front right fork is bent. I have no way of evaluating the condition of the frame, but riding her home was no fun.

I'd like to get her running again.

How expensive is it to find out if a frame has bent? Do you have to dismantle everything?

Anyways, here's some pics:

http://homepage.mac.com/mixelpix/PhotoAlbum2.html

Thanks again!
-Patrick Kennedy

[mixelpix]

Originally posted by Parr8hed
Start by checking the obvious things such as the throttle cable at the hand grip, and at the carbs. make sure that it is seated properly at both ends. also make sure that it is ajusted right at the hand grip and lubed properly. also check for air leaks at the manifolds as described in the tech section. may also need to clean the carbs well.

Hi,

The hadnlebars are currently off, but the throttle grip is still functional, along with the starter button/kill switch. I'm sure the carbs could stand a cleaning... Or three.

I was a little concened that the engine was racing. I would have thought that the varnish from gas sitting type stuff would keep the engine from running?

Three months ago (3.5 - 4? is june over already?!?) I fired her up again as well and she idled smoothly. When I was done that time I let the bike run itself off after turning the petcocks off. I also put some fuel stabilizer in the tank before filling it up (a lot of gas spilled out after it sat on it's side - thank you mercury kill switch! - with it's owner, well, busy finding out the other guy had no insurance. . .) again and otherwise prepping it for a long sit. This time I primed then, knocked the bowls a little with a rubber mallet, leaned the bike over to the left and right like a dirt biker to swirl the vapors and fluids around, and after no start, some starter fluid did the trick.

The racing was a surprise. Even with the boots off before, it idled smooth. ?.

Thanks for the suggestions!

-Patrick Kennedy

[81xsproject]

I probably almost blew my motor the first time I ran it. It turns out that in an effort to have the intake boot clamps in convienient faceing direction, when I opened up the trottle for what was supposed to be a quick rev, the throttle arm hung up on one of the clamps. I made a panic stricken flail for the kill switch and managed to shut it down before I did any damage. After 6 months on continuous restoration work I about sh@# my pants.

[mixelpix]

Yikes

yeah, I wondered about that too, but all the butterfly's seem to open and close just the way they should.

I have the throttle and choke closed and as soon as I start her up, VROOM! Like she doesn't want to level off.

I mean, I know she misses the road, but, this is a little crazy...

I'm sure there is something simple I am missing.

Thanks again everyone,
-pdk

[TopCatGr58]

Hey Patrick,

Even though the butterflies can appear closed, it only takes a little bit to have it race, especially in neutral! The idle screw is in the back middle of the carb bank, and with the impact, rubber intake boots coming off, etc., the idle screw could have gotten turned a bit in, as well as the parts getting bent, causing it to hold the butterflies open more. I'd look closely at that, see if you can turn back the idle screw a few turns, and see if the linkage will close further!? The intake boots coming off shouldn't cause a racing/runaway idle!! It's most likely in the linkage or adjustment parts of the buttefly shaft and throttle plates!
T.C.

[mixelpix]

Thanks TC!

Originally posted by TopCatGr58
Hey Patrick,
Even though the butterflies can appear closed, it only takes a little bit to have it race, ... It's most likely in the linkage or adjustment parts of the buttefly shaft and throttle plates!
T.C.

Okay - it's time to just take the carbs apart. It'll be good practice before I clean the ones on my LG!

Thanks again for the help!!

[mixelpix]

Thanks everyone!

The revving turned out to be a couple bent metal fixtures - all of which were easily bent back in to place. Essentially, the throttle was being held open. I now have a nicely restored '79SF - on to torquing everything down : )

Replaced a few dry'd out rubber parts here and there too, filters and such - I replaced the missing air intake hose from an eBay purchase - y'know, the one that makes sure the air gets through the filter! Also replaced the broken choke lever, now with original rubbers now intact. Thanks eBay!

-pdk